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<title>无标题文档</title>
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window.onload=function ()
{
	var oTxt1=document.getElementById('txt1');
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	oBtn.onclick=function ()
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		var re=/北京|百度|淘宝/g;
		
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};
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<textarea id="txt1" rows="10" cols="40"></textarea><br>
<input id="btn1" type="button" value="过滤" /><br>
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</body>
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